This invention relates to a heat exchange element employed in a heat exchanger incorporated in an air conditioning system and a method of making such a heat exchange element.
Conventionally, a so-called corrugated board type heat exchanger has been generally employed in an air conditioning system or the like. Referring to FIGS. 5 and 6, generally rectangular heat exchanging paper sheets 1 and corrugated partitions 2 formed, for example, of a special kraft paper containing calcium chloride are alternately stacked on each other. The directions of the partitions 2 are alternately changed by 90 degrees such that two perpendicular air flow passages 3 are provided. Heat exchange is performed between air flows passing through the air flow passages 3.
In the above-described conventional construction, however, the paper sheets 1 and corrugated partitions 2 are alternately stacked on each other so that each partition 2 is provided over an entire width of each paper sheet 1 at an entrance of each air flow passage 3. Furthermore, a large number of narrow passage portions are formed between the partitions 2 and the paper sheets 1 in the above-described construction. Consequently, resistance of each air flow passage is increased, resulting large air flow pressure loss.
In order to overcome the above-described disadvantage, the construction illustrated in FIGS. 7 and 8 has been proposed. Referring to FIGS. 7 and 8, a heat exchange element 7 comprises a paper sheet 5 and a plurality of partition pieces 6 formed from a synthetic resin. The partition pieces 6 are vertically mounted on one side of the paper sheet 5. A large number of such heat exchange elements 7 are stacked so that the direction of the partition pieces 6 of each heat exchange element 7 are alternately changed by 90 degrees. In this construction, each air flow passage 8 has a rectangular cross section, which can reduce the air flow pressure loss as compared with the above-described conventional construction. However, producing the above-described heat exchange element 7 necessitates a special forming step in which the synthetic resin partition pieces 6 are formed integrally with the paper sheet 5. This special forming step necessitates special production equipment and forming dies, resulting in a considerable increase in the production cost of the heat exchange element.